Jimi Hendrix, iconic rock figure of the 60s, was one of the most renowned and innovative guitarists of his day. His innovation was made possible by the development of the guitar amp.

In fact, the progression of rock music as a whole was enabled by production of the valve amp, and Edwards, now part of the Atlas Copco Group, was already involved in producing valves in the 1930s. Valves, or vacuum tubes, were by far the dominant active electronic component in most instrument amplifier applications until the 1970s, when solid-state semiconductors (transistors) started taking over.